1. Field of the Invention
The present invention relates to a joint unit which provides a cluster of up to six ball-and-socket joints.
The joint unit of the present invention was devised for making crystallographic, molecular, or geometrical models, and will be described with especial reference to this type of application. However, it is emphasised that the joint unit of the present invention can be used for any application which requires a cluster of ball-and-socket joints concentrated into a small volume: e.g. as a component of toys or jewellery.
2. Description of Prior Art
It is known to form crystallographic and molecular models from spheres (representing atoms or molecules) connected together by rods (representing interatomic or intermolecular vectors). The spheres and rods are made in a range of sizes but the angle between sphere and rod cannot be varied. A device of this type is disclosed in U.K. Pat. No. 1,256,982 (B. H. Nicholson).